Universiti Putra Malaysia, Faculty of Medicine and Health Sciences, Departments of Pathology, Selangor, Malaysia.
Malays J Pathol. 2021 Apr;43(1):75-79.
Cutaneous multiple myeloma (MM) is a rare disease. It can be primary or secondary in origin. The secondary type is further classified into specific and nonspecific types. The specific type is uncommon and is known as a secondary cutaneous plasmacytoma. We report a case of secondary cutaneous plasmacytoma in a 58-year-old man who had a history of plasma cell tumour of the lung and multiple myeloma. He achieved complete remission after the completion of chemotherapy and autologous stem cell transplant (ASCT). However, five months later, he developed multiple erythematous nodules on the whole body. Skin biopsy revealed diffuse neoplastic cells infiltrate in the reticular dermis with sparing of the upper papillary dermis and epidermis. The neoplastic cells were monotonous and homogenous with variable degrees of cytological atypia. Occasional cells showed distinctive plasma cell features. Plasma cell lineage was confirmed with CD138. The cells were immunoreactive to Kappa. Ki-67 was greater than 90%. They were non-immunoreactive to CD45, CD3, CD20, CD79 alpha and CK AE1/AE3. The findings were consistent with secondary cutaneous plasmacytoma. Our case illustrates that MM may present with nonspecific dermatological manifestations. As specific cutaneous involvement of MM is very uncommon; a high degree of clinical suspicion, detailed medical history and histopathological examination are required to arrive at an early diagnosis.
皮肤多发性骨髓瘤（MM）是一种罕见的疾病。它可以是原发性的，也可以是继发性的。继发性类型进一步分为特异性和非特异性类型。特异性类型不常见，被称为继发性皮肤浆细胞瘤。我们报告一例 58 岁男性的继发性皮肤浆细胞瘤病例，该患者曾患有肺浆细胞瘤和多发性骨髓瘤。他在完成化疗和自体干细胞移植（ASCT）后达到完全缓解。然而，五个月后，他全身出现多个红斑性结节。皮肤活检显示弥漫性肿瘤细胞浸润在网状真皮中，乳头真皮和表皮不受累。肿瘤细胞均匀一致，具有不同程度的细胞学异型性。偶尔细胞表现出独特的浆细胞特征。用 CD138 证实浆细胞系。细胞对 Kappa 呈免疫反应性。Ki-67 大于 90%。它们对 CD45、CD3、CD20、CD79 alpha 和 CK AE1/AE3 无免疫反应性。这些发现与继发性皮肤浆细胞瘤一致。我们的病例表明，MM 可能表现为非特异性皮肤表现。由于 MM 的特异性皮肤受累非常罕见；需要高度的临床怀疑、详细的病史和组织病理学检查才能做出早期诊断。
